Tuning the Magnetic Properties of Kitaev Materials via the Antiferromagnetic Proximity Effect: Novel Phases and Application to an α-RuCl₃/MnPS₃ Bilayer

In recent years, the increasing level of control over van der Waals (vdW) heterostructures has opened new routes to tune the properties of quantum materials. Motivated by these developments, we examine the potential consequences of interfacing a Kitaev honeycomb magnet, such as α-RuCl₃, with a nearly lattice-matched vdW antiferromagnet. By combining perturbation theory, exact diagonalization, and a classical energy-minimization method, we show that an effective staggered magnetic field originating from the vdW antiferromagnet can drive a monolayer of a Kitaev material into various novel phases, including an antichiral Kitaev spin liquid, a nonmagnetic nematic phase, and different types of skyrmion crystals. We then apply first-principles simulations to assess the prospect of concretely realizing this setup in a heterobilayer of α-RuCl₃ and the easy-axis antiferromagnet MnPS₃.